Computation Method for the Real-Time Control Problems in Differential-Algebraic Systems

In this paper, a real-time computation method for the control problems in differential-algebraic systems is presented. The errors of the method are estimated, and the relation between the sampling stepsize and the controlled errors is analyzed. The stability analysis is done for a model problem, and the stability region is ploted which gives the range of the sampling stepsizes with which the stability of control process is guaranteed.

Adapting Backward Error Recovery to Parallel Real Time Systems

The problem of adapting backward error recovery to parallel real time systems is discussed in this paper. Because of error propagation among different cooperating processes, an error occurring in one process may influence some important outputs in other processes. Therefore, a local output has to be delayed until its validity is confirmed globally. Since backward error recovery adopts redundancy of computing time instead of processing equipment, the variation of the actual execution time of a cooperating process may be very large if it works in an unreliable environment. These problems are the primary obstacles to be removed. Previous studies focus their attentions on how to eliminate domino-effect dynamically. But backward error recovery cannot be applied directly in parallel real time systems even under the condition that no domino-effect exists. How to reduce output delays efficiently if no domino-effect remains? How to estimate this delay time? How to calculate the actual execution time of every process and how to schedule these processes under an unstable condition? These problems were omitted in literature unfortunately. The interest of this paper is to provide satisfactory solutions to these problems to make it possible to adopt backward error recovery efficiently in parallel real time systems.

Weak Serializable Concurrency Control in Distributed Real-Time Database Systems

Most of the proposed concurrency control protocols for real time database systems are based on serializability theorem. Owing to the unique characteristics of real time database applications and the importance of satisfying the timing constraints of transactions, serializability is too strong as a correctness criterion and not suitable for real time databases in most cases. On the other hand, relaxed serializability including epsilon serializability and similarity serializability can allow more real time transactions to satisfy their timing constraints, but database consistency may be sacrificed to some extent. We thus propose the use of weak serializability(WSR) that is more relaxed than conflicting serializability while database consistency is maintained. In this paper, we first formally define the new notion of correctness called weak serializability. After the necessary and sufficient conditions for weak serializability are shown, corresponding concurrency control protocol WDHP(weak serializable distributed high priority protocol) is outlined for distributed real time databases, where a new lock mode called mask lock mode is proposed for simplifying the condition of global consistency. Finally, through a series of simulation studies, it is shown that using the new concurrency control protocol the performance of distributed real time databases can be greatly improved.

Multi-Threat Real-Time Separating System

This paper describes a multi-threat real-time separating system for broadband anti-radiation missile seeker. It presents a method, with a dual-port memory as comparer, to perform PF and PW hardware real-time separation and to determine the time-of-arrival (TOA) by use of sequential difference histogram (SDIF). The method has been applied to practice, which has achieved good results.

On-Line Real Time Realization and Application of Adaptive Fuzzy Inference Neural Network

In this paper, a modeling algorithm developed by transferring the adaptive fuzzy inference neural network into an on-line real time algorithm, combining the algorithm with conventional system identification method and applying them to separate identification of nonlinear multi-variable systems is introduced and discussed.

An Automatic Testing System of Scheduling Strategies in Real-Time UNIX

This paper proposes a formal model of the automatic testing system for scheduling strategies in real-time UNIX and describes the algorithm of the key part of the system. The model of the system is an important technology of the automatization of software development. According to the model presented in the paper, many different kinds of automatic testing systems can be designed and developed easily. At the end of the paper, the prototype proves the feasibility of the model and design.

High performance reconfigurable hardware system for real-time image processing

A novel reconfigurable hardware system which uses both muhi-DSP and FPGA to attain high performance and real-time image processing are presented. The system structure and working principle of mainly processing multi-BSP board, extended multi-DSP board are analysed. The outstanding advantage is that the communication among different board components of this system is supported by high speed link ports ＆ serial ports for increasing the system performance and computational power. Then the implementation of embedded real-time operating systems （RTOS） by us is discussed in detail. In this system, we adopt two kinds of parallel structures controlled by RTOS for parallel processing of algorithms. The experimental results show that exploitive period of the system is short, and maintenance convenient. Thus it is suitable for real-time image processing and can get satisfactory effect of image recognition.

An advanced discrete‐time RNN for handling discrete time‐varying matrix inversion:Form model design to disturbance‐suppression analysis

Time‐varying matrix inversion is an important field of matrix research,and lots of research achievements have been obtained.In the process of solving time‐varying matrix inversion,disturbances inevitably exist,thus,a model that can suppress disturbance while solving the problem is required.In this paper,an advanced continuous‐time recurrent neural network(RNN)model based on a double integral RNN design formula is pro-posed for solving continuous time‐varying matrix inversion,which has incomparable disturbance‐suppression property.For digital hardware applications,the corresponding advanced discrete‐time RNN model is proposed based on the discretisation formulas.As a result of theoretical analysis,it is demonstrated that the advanced continuous‐time RNN model and the corresponding advanced discrete‐time RNN model have global and exponential convergence performance,and they are excellent for suppressing different disturbances.Finally,inspiring experiments,including two numerical experiments and a practical experiment,are presented to demonstrate the effectiveness and superiority of the advanced discrete‐time RNN model for solving discrete time‐varying matrix inversion with disturbance‐suppression.

A Priority-aware Frequency Domain Polling MAC Protocol for OFDMA-based Networks in Cyber-physical Systems

Wireless networking in cyber-physical systems (CPSs) is characteristically different from traditional wireless systems due to the harsh radio frequency environment and applications that impose high real-time and reliability constraints. One of the fundamental considerations for enabling CPS networks is the medium access control protocol. To this end, this paper proposes a novel priority-aware frequency domain polling medium access control (MAC) protocol, which takes advantage of an orthogonal frequency-division multiple access (OFDMA) physical layer to achieve instantaneous priority-aware polling. Based on the polling result, the proposed work then optimizes the resource allocation of the OFDMA network to further improve the data reliability. Due to the non-polynomial-complete nature of the OFDMA resource allocation, we propose two heuristic rules, based on which an efficient solution algorithm to the OFDMA resource allocation problem is designed. Simulation results show that the reliability performance of CPS networks is significantly improved because of this work. © 2014 Chinese Association of Automation.

A Theory for the Initial Allocating of Real Time Tasks in Distributed Systems

Referring to a set of real time tasks with arriving time,executing time and deadline,this paperdiscusses the problem of polynomial time initial-allocating approximation algorithms in a distributedsystem and five new results are gained which provide a theory for the designing of initial-allocating algorithmsof real time tasks.

Research on Guaranteed Scheduling Algorithms

Guaranteed scheduling is necessary for hard real time systems, because each process of them must meet their deadline, or a serious consequence will result.In this paper we discuss two guaranteed schedule algorithms:backtracking and branch and bound,introduce the process to find the optimal solution by both methods,propose the concept of logical node and physical node.Through some experiments for different process sets,we have made comparisons between the two algorithms in branch nodes,comparing time,topology of the search tree,memory size needed,etc.

Study on Transformer Magnetic Biasing Control Method for AC Power Supplies

This paper presents a novel transformer magnetic biasing control method for high-power high-performance AC power supplies. Serious consequences due to magnetic biasing and several methods to overcome magnetic biasing are first discussed. The causes of the transformer magnetic biasing are then analyzed in detail. The proposed method is based on a high-pass filter inserted in the forward path and the feedforward control. Without testing magnetic biasing of transformer, this method can eliminate magnetic biasing of transformer completely in real-time waveform feedback control systems though the zero error of the Hall effect sensors varies with time and temperature. The method has already been employed in a 90KVA AC power supply. It is shown that it offers improved performance over existing ones. In this method, no sensors are used such that the zero error of the Hall effect sensors has not any influence on the system. It is simple to design and implement. Furthermore, the method is suitable for various power applications.

Sinusoidal phase-modulating laser diode interferometer for real-time surface profile measurement

A sinusoidal phase-modulating （SPM） laser diode （LD） interferometer for real-time surface profile measurement is proposed and its principle is analyzed. The phase signal of the surface profile is detected from the sinusoidal phase-modulating interference signal using a real-time phase detection circuit. For 60 × 60 measurement points of the surface profile, the measuring time is 10 ms. A root mean square （RMS） measurement repeatability of 3.93 nm is realized, and the measurement resolution reaches 0.19 nm.

HIL Simulation of a Mixed Islanded Power Network with External DSP Regulator

The present paper deals with the development of a modular, flexible and structured block to block approach for the study of regulators by implementing the different blocks on a DSP （digital signal processor）. The proposed low-cost approach has been applied and validated by the implementation of an industrial regulator in a real time hardware-in-the-loop simulation of a mixed islanded power network including precise models of the hydraulic system. The studied network is constituted of three different types of electrical power generation systems and a consumer.

Measurement of spatial object's exterior attitude based on linear CCD

It is difficult to realize real-time measurement of exterior attitude by the traditional systems based on the area image sensor which have conflict between speed and accuracy. The subsystem for three-dimensional （3D） coordinate reconstruction of point target （S3DCRPT） which is composed of three one-dimensional （1D） cameras based on linear charge-coupled device （CCD） can determine the distant light spots＇ spatial position. The attitude angle of the measured object is determined by the spatial solution while the coordinate reconstruction is separately carried on by the S3DCRPT with some point cooperation targets （PCTs） on the measured object. A new optical system is designed to solve the interference problem with one-to-one relationship between the PCTs and the S3DCRPT optical subsystems, which improves the measurement accuracy and saves space. The mathematical model of the attitude measurement is established, and partial and global calibrations are realized for the multi-camera attitude measurement system. The test results show the feasibility of the exterior attitude measurement based on linear CCD.

Coarse error analysis and correction of a two-dimensional triangulation range finder

A real-time two-dimensional （2D） triangulation range finder is presented, which is composed of two linear complementary metal oxidation semiconductor （CMOS） chips, two camera lenses, and four light emitting diodes （LEDs）. The high order distortion in image aberrations is the main factor responsible for the coarse errors. The theoretical prediction is in good agreement with experiments and the correction equation is used to obtain more reliable results with the unique distortion coefficient in tile whole working region.

Vehicle detection and tracking based on phase-correlation

This paper presents vehicle detection and tracking algorithms based on real-time background (RTB) and phase-correlation (PC) in the video sequence of urban highway with fixed camera. Firstly moving objects are obtained by subtracting RTB from serial images. After classification, PC is used to determine corresponding regions of moving objects between consecutive frames. The problems of vehicles' merging and splitting, sudden stop, and restart are also considered. Experiments show that the method is practical and can realize real-time detection and tracking of vehicles on highway.

All-optical sampling OFDM system performance analysis

The performance of a novel all-optical sampling orthogonal frequency division multiplexing （OFDM） system is proposed and analyzed. Time delays and phase shifters are used to realize all optical forward/inverse discrete Fourier transform （DFT/IDFT）. Different system configurations are tested and analyzed to op- timize the performance, including the system capacity, modulation formats, DFT/IDFT constructions, and the width of the sample pulse. The 50- and 100-Gb/s real-time all-optical sampling （AOS） OFDM systems ave investigated. All results are analyzed, and useful suggestions are offered for future high-speed

POTENTIAL APPLICATION FOREGROUND OF OCEAN MODE IN NAVY OCEANOGRAPHY

Ocean mode (or quasigeostrophic wave) analysis is one of the key data processing technique in oceanic acoustic tomography experiment. A primary study on its application foreground in Navy Oceanography is put forward with CTD data and Carton oceanic assimilation data. It shows that the sound speed mode is not well orthogonal to each other, so that it is practically no use. However, the current mode calculated from the CTD data collected in summer as the position with weak stochastic processes and strong geostrophic balance is well orthogonal to each other, it can be used everywhere in the ocean of the similar water mass at any time as long as the basic condition serves. It can be used for decomposition and reconstruction of dynamic or quasi-dynamic factors such as seawater temperature, from which and average of salinity the sound speed profile can be composed. It also shows that the monthly James Carton assimilation data is well consistent with observation ones in subsurface layer in the region with weak current speed but not well below subsurface layer or near the Kuroshio in the western Pacific. By running a nested ocean general circulation model with adjusted vertical eddy diffusivity to do data assimilation again and applying current mode analysis to reconstruct or compose related factors, it is hopefully possible to improve the precision and space resolution of the oceanic assimilation data. So that, it is definitely possible to obtain the three dimensional high resolution distribution of ocean sound speed in real time with the satellite SST and surface wind fields only.